Sclerostin is a secreted glycoprotein with a C-terminal cysteine knot-like domain and sequence similarity to the DAN family of bone morphogenetic protein antagonists. Sclerostin is produced by the osteocyte and has anti-anabolic effects on bone formation. Sclerostin, the product of the SOST gene, located on chromosome 17q12–q21 in humans, was originally believed to be a non-classical bone morphogenetic protein (BMP) antagonist. More recently sclerostin has been identified as binding to LRP5/6 receptors and inhibiting the Wnt signaling pathway. Mutations in the gene sclerostin are associated with disorders associated with high bone mass, sclerosteosis and van Buchem disease.